Numerical optimization approach to modelling delamination and buckling of geometrically constrained structures.

Understanding what happens in terms of delamination during buckling of laminate materials is of importance across a range of engineering sectors. Normally concern is that the strength of the material is not significantly impaired. Carton-board is a material with a laminate structure and, in the initial creation of carton nets, the board is creased in order to weaken the structure. This means that when the carton is eventually folded into its three-dimensional form, correct folding occurs along the weakened crease lines. Understanding what happens during creasing and folding is made difficult by the nonlinear nature of the material properties. This paper considers a simplified approach which extends the idea of minimizing internal energy so that the effects of delamination can be handled. This allows a simulation which reproduces the form of buckling-delamination observed in practice and the form of the torque-rotation relation.

Genetic differentiation in Scottish populations of the pine beauty moth, Panolis flammea (Lepidoptera: Noctuidae).

Pine beauty moth, Panolis flammea (Denis & Schiffermüller), is a recent but persistent pest of lodgepole pine plantations in Scotland, but exists naturally at low levels within remnants and plantations of Scots pine. To test whether separate host races occur in lodgepole and Scots pine stands and to examine colonization dynamics, allozyme, randomly amplified polymorphic DNA (RAPD) and mitochondrial variation were screened within a range of Scottish samples. RAPD analysis indicated limited long distance dispersal (FST=0.099), and significant isolation by distance (P<0.05); but that colonization between more proximate populations was often variable, from extensive to limited exchange. When compared with material from Germany, Scottish samples were found to be more diverse and significantly differentiated for all markers. For mtDNA, two highly divergent groups of haplotypes were evident, one group contained both German and Scottish samples and the other was predominantly Scottish. No genetic differentiation was evident between P. flammea populations sampled from different hosts, and no diversity bottleneck was observed in the lodgepole group. Indeed, lodgepole stands appear to have been colonized on multiple occasions from Scots pine sources and neighbouring populations on different hosts are close to panmixia.

Effects of simvastatin on blood lipids, vitamin E, coenzyme Q10 levels and left ventricular function in humans.

BACKGROUND: As statin therapy has been reported to reduce antioxidants such as vitamin E and coenzyme Q10 and there are indications that this reduction may cause impairment of left ventricular function (LVF), we studied the influence of simvastatin on LVF and serum vitamin E and coenzyme Q10 levels in humans. MATERIAL AND METHODS: We assessed the effect of simvastatin on left ventricular function and coenzyme Q10 levels in 21 (11 male, 10 female) hypercholesterolaemic subjects (mean age = 56 years) with normal LVF, over a period of 6 months. Subjects were re-tested after a 1-month wash-out period (7 months). Echocardiography was performed on all subjects before commencement of simvastatin (20 mg day(-1)), and at 1, 3, 6 and 7 months after initiation of treatment. Fasting blood samples were also collected at these intervals to assess lipids, apoproteins, vitamin E and coenzyme Q10. RESULTS: Serum lipids showed the expected reductions. Plasma vitamin E and coenzyme Q10 levels were reduced by 17 +/- 4% (P < 0.01) and 12 +/- 4% (P < 0.03) at 6 months. However, the coenzyme Q10/LDL-cholesterol ratio and vitamin E/LDL-cholesterol ratio increased significantly. Left ventricular ejection fraction (EF) decreased transiently after 1 month, while no significant change was observed at 3 and 6 months. Other markers of left ventricular function did not change significantly at any time point. CONCLUSION: Despite reduced plasma vitamin E and coenzyme Q10, 20 mg of simvastatin therapy is associated with a significantly increased coenzyme Q10/LDL-cholesterol ratio and vitamin E/LDL-cholesterol ratio. Simvastatin treatment is not associated with impairment in left ventricular systolic or diastolic function in hypercholesterolaemic subjects after 6 months of treatment.

Presentation and diagnosis of adolescent breast disease.

Breast disease in the adolescent female is fortunately uncommon, with most presenting lesions being benign. The type and frequency of breast problems in young women less than 20 years of age are discussed in this paper. There were 634 adolescent females (9-19 years) referred to the Wesley Breast Clinic between January 1990 and December 1999. Of these, 62.6% were aged 18-19 years. The commonest reason for referral was a lump or thickening in the breast (n=554, 87.4%). Six hundred and nineteen females had ultrasound performed, with 59% showing no abnormality. The commonest abnormality in the remainder was probable fibroadenoma (n=162). Twenty-two percent of the females in the study had fine needle aspiration performed; none showed suspicious cytology. Twenty-three females had an excision biopsy following their initial visit. Three of these were found to have benign phyllodes tumour. There were no malignancies detected, although one female had previous DCIS diagnosed elsewhere.

Phenolic content of olive oil is reduced in extraction and refining.

Three grades of olive oil and ten vegetable cooking oils were analysed for their phenolic content. It was hypothesised that as olive oil passed through the chemical extraction process, polyphenols would also be removed, thus reducing the antioxidant properties of olive oil. Other commonly used edible vegetable oils were analysed for comparative reasons. Extra virgin olive oil was found to have the greatest amount (48 µg/gram of oil) of polyphenols, when compared with other olive or vegetable oils. No polyphenols were detected in sunflower, walnut, peanut or almond oils. All other oils tested had a polyphenolic content between 2 and 10 µg/gram of oil. The results of the study confirms the above hypothesis that the phenolic content of olive oil is reduced by chemical extraction and refining.

Nitrogen Fixation Associated with the New Zealand Mangrove (Avicennia marina (Forsk.) Vierh. var. resinifera (Forst. f.) Bakh.).

Nitrogenase activity in mangrove forests at two locations in the North Island, New Zealand, was measured by acetylene reduction and N(2) uptake. Nitrogenase activity (C(2)H(2) reduction) in surface sediments 0 to 10 mm deep was highly correlated (r = 0.91, n = 17) with the dry weight of decomposing particulate organic matter in the sediment and was independent of light. The activity was not correlated with the dry weight of roots in the top 10 mm of sediment (r = -0.01, n = 13). Seasonal and sample variation in acetylene reduction rates ranged from 0.4 to 50.0 mumol of C(2)H(4) m h under air, and acetylene reduction was depressed in anaerobic atmospheres. Nitrogen fixation rates of decomposing leaves from the surface measured by N(2) uptake ranged from 5.1 to 7.8 nmol of N(2) g (dry weight) h, and the mean molar ratio of acetylene reduced to nitrogen fixed was 4.5:1. Anaerobic conditions depressed the nitrogenase activity in decomposing leaves, which was independent of light. Nitrogenase activity was also found to be associated with pneumatophores. This activity was light dependent and was probably attributable to one or more species of Calothrix present as an epiphyte. Rates of activity were generally between 100 and 500 nmol of C(2)H(4) pneumatophore h in summer, but values up to 1,500 nmol of C(2)H(4) pneumatophore h were obtained.